The present invention relates generally to aircraft ground handling systems and, more particularly, to a device for lifting an aircraft wheel assembly.
According to one aspect of the present invention, there is provided a device for lifting a wheel assembly of an aircraft, such as a twin nose-wheel assembly, for aircraft ground handling purposes. The device comprises first and second wheel supports which are rotatable relative to one another between a first configuration in which a first portion of the aircraft wheel circumference can be located against the first support and a second configuration in which the second support is brought against a second portion of the wheel circumference, opposite the first portion, to cradle the wheel, the supports being raisable and lowerable in the second configuration.
Although the present invention is shown and described as a self-propelled towing dolly or the like, the device, it is understood, may also constitute part of an aircraft ground handling machine or the like, giving consideration to the purpose for which the present invention is intended. It is preferred, alternatively or concurrently therewith, that the device also include a connection to a bearing structure or chassis of an aircraft ground handling machine to enable raising and lowering of the wheel support and wheel cradled thereby.
According to another aspect of the present invention, there is provided an aircraft ground handling machine, such as a towing dolly or a tractor, having a device according to the first aspect of the invention.
For instance, at least one of the wheel supports is constituted by wheel engaging surfaces, and comprise a fixed support which defines the first support surface and a movable support which defines the second support surface and is rotatable relative to the fixed support. Alternatively or concurrently, the wheel supports may each comprise laterally-disposed and vertically spaced-apart pins which define notional wheel-engaging surfaces but which have an advantage of having utility irrespective of the diameter of the wheel. The supports may also be rotatable relative to one another about an axis which is substantially vertical in the normal condition of use, so that the supports close like a jaw laterally around the wheel.
Preferably, the movable wheel supports rotate relative to the fixed wheel support about a transverse axis which is substantially horizontal in the normal condition of use, the movable support being disposed on the same side of the wheel as the fixed support (that is, adjacent the first portion of the wheel circumference) in the first configuration and being swung over the wheel into the second configuration so that, in the second configuration, the movable supports are disposed on the opposite side of the wheel from the fixed support. Where the wheel supports comprise wheel-engaging surfaces, they are preferably curved surfaces which are concentric or substantially concentric about the transverse axis. Alternatively or concurrently therewith, the wheel supports, as indicated above, comprise pins which may be carried by side plates for location and rotation purposes relative to the wheel and may be themselves rotatable or may carry rotatable sleeves.
It is preferred, such as in the case of lifting of a twin nosewheel assembly, the first support surface of the fixed wheel support corresponds substantially in width to the overall width of the twin nosewheel and is engagable by the two wheels thereof. It is also preferred in this context that the movable wheel support comprise two members which are rotatable in unison over respective wheels of the twin nosewheel assembly, on either side of the central nosewheel strut, commonly known as an oleo leg, and each of which defines a respective second support surface portion engagable with the respective wheel in the second configuration.
It is further preferred that, on the first support surface, there be two pressure switches operable by the two wheels of the twin nosewheel to enable rotation of at least one movable wheel support, the pressure switches being in positions such that they can both be operated to enable rotation of the movable support only when the twin nosewheel is correctly positioned against the first support surface. This prevents the movable wheel support from operating in a misaligned condition of the nosewheel and hence from fouling the nosewheel.
Accordingly, it is an object of the present invention to provide ready lifting of an aircraft nosewheel assembly for improved transport of aircraft which is not only suitable for use in confined (and unconfined) areas, but also durable, reliable and economical.